For insulating purposes, especially in this period of great sensitivity toward energy waste, double-pane and multi-pane windows are of paramount importance to prevent loss of heat or incursion of heat through the portion of a structure wall provided with the window.
It is thus known to provide an insulated window structure having two or more transparent panes, usually of glass, which are separated by a dead air space defined between the panes with the aid of a peripheral spacer. In other words, the two panes are held apart by a spacer and lie against the opposite planar walls of the spacer which are turned outwardly.
The spacer generally consists of a frame of hollow profiles which are joined together and have planar outwardly turned faces against which the glass panes lie. The inwardly turned profile walls are substantially flat or planar as well. The walls of the profile may have crevices and the hollow interior thereof can receive a drying agent capable of absorbing moisture.
Systems of the latter type are provided, for example, in German Federal Republic Pat. Nos. 1,434,175 and 1,509,170. In these systems, the hollow profiles are joined into a frame by specially designed corner connectors and a problem has been encountered with these systems in that the connection between the glass panes and the frame cannot be completely sealed at the corner regions to prevent penetration of moisture into the space between the panes and defined by the spacer frame. The hollow interior is filled with a dried gas, for example air, and the penetration of moisture is largely prevented by the sealing materials to prevent condensation within the interior of the window, e.g. along the inner faces of the glas panes.
Surprisingly, while it is possible to adequately seal the panes to the frame along the rectilinear portions of the latter, i.e. the major portions of the sides thereof, using an appropriate adhesive or sealer, the seal at the corners does not appear to be as effective and the corner regions thus permit more or less moisture to penetrate.
It has been sought, e.g. by the proposal of German Federal Republic Pat. No. 1,509,170, to obviate this disadvantage by beveling the corner-connecting angle and providing a thicker deposit of the sealing mass in this region. This attempt is designed to increase the length over which diffusion must occur from the exterior into the enclosed space of the window.
In practice, this has proved to be largely unsuccessful and even attempts by the use of additional adhesive materials, soldering or like treatments to seal the corner regions have proved to be unsuccessful either as a result of their extraordinarily high cost or their unsatisfactory ability to effect a truly hermetic seal.